RESUMO
We present calculated scattering lengths for collisions between various isotopic forms of lithium and hydrogen atoms interacting via singlet and triplet molecular states of LiH. We demonstrate that one bound triplet level is supported for each isotopomer 7LiH, 6LiH, 7LiD, and 6LiD. We obtain large calculated triplet scattering lengths that are stable against uncertainties in the potential. We present elastic and momentum transfer cross sections, and the corresponding rate coefficients, for hydrogen atoms colliding with 7Li atoms. We suggest that enhanced cooling of trapped atomic hydrogen by 7Li atoms is feasible.
RESUMO
Three pigments of the guaiazulene class have been isolated from the gorgonian Calicogorgia granulosa. Structures of these compounds have been determined as guaiazulene, 2,2'- diguaiazulenylmethane, and a new compound, 2,2'-biguaiazulenyl, by combined chemical and spectroscopic methods. 2,2'-Biguaiazulenyl exhibited moderate antimicrobial activity.
Assuntos
Anti-Infecciosos/isolamento & purificação , Cnidários/química , Sesquiterpenos/isolamento & purificação , Animais , Antibacterianos , Anti-Infecciosos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Azulenos , Bacillus subtilis/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Sesquiterpenos/farmacologia , Sesquiterpenos de GuaianoRESUMO
The predissociation of the 1(3)Sigma(-)(g) v >/= 10 levels of (7)Li(2) has been observed by pulsed and continuous-wave perturbation-facilitated optical-optical double-resonance spectroscopy (PFOODR). Our ab initio calculation shows that the inner wall of the 1(3)Sigma(-)(g) potential intersects the 1(3)Pi(g) repulsive potential at internuclear distance R = 2.00 Å. The predissociation is due to a DeltaS = 0, DeltaLambda = +/-1 rotational-electronic interaction with the repulsive 1(3)Pi(g) state. Copyright 2001 Academic Press.